Experimental comparison of properties of natural and synthetic osmotic dilators

The in vitro study compares natural and synthetic osmotic dilators in selected parameters influencing their clinical efficacy. Diameters of Laminaria and synthetic dilators (Dilapan-S and Dilasoft) were measured in dry state, during free swelling in isotonic solution and during swelling against a force. Three aspects were evaluated-diameter increase, speed of action and consistency of action. The maximum diameter increase of 3 and 4-mm Dilapan-S was 3.6 and 3.3 times, of Dilasoft 3.2 and 3.1 times, respectively. For Laminaria, it was 2.9 and 2.7 times. The difference between synthetic dilators and Laminaria was statistically significant (p < 0.01). Synthetic dilators also swelled faster. Under applied counter force, synthetic dilators increased their diameter more than Laminaria (+3.6 mm for Dilapan-S, +3.8 mm for Dilasoft, +1.2 mm for Laminaria; p < 0.01) and achieved faster expansion. Synthetic dilators also showed significantly higher consistency between samples in all experiments. Synthetic dilators compared to Laminaria reached higher maximum diameters, acted faster, were more consistent and were able to expand against force three times more. The results support clinical observations that synthetic dilators are more suitable and preferable for same-day D&E procedure and that fewer synthetic dilators are needed to achieve the same effect.